Howdy All
I have a 2000 4 runner 3.4L automatic that would not go into 4wd no light nothing. After checking this forum and reading about others that have had this problem, I proceeded to check switch's, actuator, vcsv's, vac. line's, Etc.
what I found was that the vac. line coming from the vcsv to engage 4wd had no vac. at actuator. but had vac. at vcsv, After putting compressed air to that line I have vac. at actuator 4wd go's right in, Light comes on Just as it should So I am not saying this will fix anyone else's, But it just go's to show "Check those vac. line's" Not only can you have a vac. leak
A plugged line will give you just as much trouble "Fix it by the fire Keep away the Zombies"